mitoguazone and 1-4-benzoquinone-guanylhydrazone-thiosemicarbazone

Ambazone (1,4-benzoquinone guanylhydrazone thiosemicarbazone) was found to be active against various transplantable tumors in mice as well as rats. When administered orally for 4-9 days, the effective therapeutic dose ranged between 60 and 125 mg/kg. The antineoplastic effect of ambazone appeared to be mediated, at least in part, by the immune system. In order to characterize the drug, biophysical and biophysicochemical studies were carried out using thin-layer chromatography, absorption spectroscopy and polarographic measurements. The distribution of ambazone in an n-octanol/water system indicated low hydrophobicity, thereby excluding the possibility of a preferential contribution from hydrophobic forces to the mode of action of ambazone. Ambazone undergoes three protonation reactions with pK values at 10.69 (equilibrium between the negatively charged and neutral forms), 7.39 (equilibrium between the neutral and singly positively charged form) and 6.22 (equilibrium between the singly and doubly positively charge form). Interaction of the drug with model membrane system was monitored by spectrophotometric and fluorescence measurements. Using the fluorescence label 1-anilino-8-naphthalenesulfonic acid (ANS) as a probe pointed to the interaction of ambazone with the inner area of the phospholipid bilayer matrix of liposomes as being nonspecific. Ambazone induces an overall increase in the cellular cAMP content of leukemia cells and macrophages. So far, membrane interaction has provided a molecular basis for both immunological and antineoplastic activities of the drug. By performing DNA melting experiments, it was shown that neutral or singly positively charged ambazone species stabilize the secondary structure of DNA, while the doubly positively charged form binds more strongly and destabilizes the DNA. After oral administration to rats and mice, ambazone was found to be incompletely absorbed from the gastrointestinal tract, to an extent of about 35-50%. Absorbed ambazone binds only weakly to plasma proteins, whereas its binding to red blood cells is relatively strong. The mutagenic potential of ambazone shown in bacterial systems and human lymphocytes corresponds to its relatively weak interaction with DNA. The toxic action of ambazone on the intestine is believed to be due to inhibition by the drug of bacterial DNA, RNA and protein syntheses. It is assumed that the reported affinity of ambazone for different cellular targets, i.e., membranes, nucleic acid

Topics: Animals; Antineoplastic Agents; Cell Membrane; Humans; Mitoguazone

Tyrosinase catalyzes two distinct sequential reactions in melanin biosynthesis: The hydroxylation of tyrosine to dihydroxyphenylalanine (DOPA) and the oxidation of DOPA to dopaquinone. Developing functional modulators of tyrosinase is important for therapeutic and cosmetic purposes. Given the abundance of thiourea moiety in known tyrosinase inhibitors, we studied other thiourea-containing drugs as potential tyrosinase inhibitors. The thiourea-containing drugs in clinical use were retrieved and tested for their ability to inhibit tyrosinase. We observed that methimazole, thiouracil, methylthiouracil, propylthiouracil, ambazone, and thioacetazone inhibited mushroom tyrosinase. Except for methimazole, there was limited information regarding the activity of other drugs against tyrosinase. Both thioacetazone and ambazone significantly inhibited tyrosinase, with IC50 of 14 and 15 μM, respectively. Ambazone decreased melanin content without causing cellular toxicity at 20 μM in B16F10 cells. The activity of ambazone was stronger than that of kojic acid both in enzyme and melanin content assays. Kinetics of enzyme inhibition assigned the thiourea-containg drugs as non-competitive inhibitors. The complex models by docking simulation suggested that the intermolecular hydrogen bond via the nitrogen of thiourea and the contacts via thione were equally important for interacting with tyrosinase. These data were consistent with the results of enzyme assays with the analogues of thiourea.

Topics: Animals; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Drug Repositioning; Enzyme Inhibitors; Humans; Kinetics; Melanins; Melanoma, Experimental; Mice; Mitoguazone; Models, Molecular; Molecular Conformation; Monophenol Monooxygenase; Protein Binding; Thiourea

The crystal structures of the monohydrate and anhydrous forms of ambazone were determined by single-crystal X-ray diffraction (SC-XRD). Ambazone monohydrate is characterized by an infinite three-dimensional network involving the water molecules, whereas anhydrous ambazone forms a two-dimensional network via hydrogen bonds. The reversible transformation between the monohydrate and anhydrous forms of ambazone was evidenced by thermal analysis, temperature-dependent X-ray powder diffraction and accelerated stability at elevated temperature, and relative humidity (RH). Additionally, a novel ambazone acetate salt solvate form was obtained and its nature was elucidated by SC-XRD. Powder dissolution measurements revealed a substantial solubility and dissolution rate improvement of acetate salt solvated form in water and physiological media compared with ambazone forms. Also, the acetate salt solvate displayed good thermal and solution stability but it transformed to the monohydrate on storage at elevated temperature and RH. Our study shows that despite the requirement for controlled storage conditions, the acetate salt solvated form could be an alternative to ambazone when solubility and bioavailability improvement is critical for the clinical efficacy of the drug product.

Topics: Acetates; Chemistry, Pharmaceutical; Crystallization; Crystallography, X-Ray; Drug Stability; Humidity; Hydrogen Bonding; Kinetics; Mitoguazone; Models, Molecular; Molecular Structure; Powder Diffraction; Powders; Solubility; Technology, Pharmaceutical; Temperature; Water

In order to improve the bioavailability of insulin after rectal application to rabbits, the influence of surface-active amino acid-fatty acid condensate on absorption and, the effects of a protease inhibitor (aprotinine), of a disinfectant (methyl-hydroxybenzoate) and of chemotherapeutics (chloramphenicol, ambazone and metronidazole) were investigated. Only the application of methylhydroxybenzoate, ambazone and of metronidazole, which inhibit the anaerobic bacterial flora, improved bioavailability significantly. The examinations show that the proteolytic activity of the anaerobic bacterial flora causes the loss of the biological activity of peptides in the rectum.

Topics: Administration, Rectal; Animals; Anti-Bacterial Agents; Aprotinin; Bacteria, Anaerobic; Biological Availability; Blood Glucose; Chinchilla; Chloramphenicol; Insulin; Intestines; Male; Metronidazole; Mitoguazone; Parabens; Protease Inhibitors; Rabbits; Suppositories

The influence of age of experimental animals on the antileukemic activity, toxicity and distribution of ambazone, a new potential antineoplastic agent, was studied in 2- and 12-month-old B6D2F1 mice. The predominant effect observed was a significant reduction of the antileukemic action of this compound in old-aged mice. Together with a slight increase in several toxicity parameters this caused a marked reduction of the therapeutic index in 12-month-old mice compared to younger individuals. Furthermore, a general tendency to increased ambazone levels in liver, kidneys and thymus of old-aged mice was observed. Our data therefore provide further evidence that age has to be taken into consideration as one factor that may account for the variety of drug response frequently observed during clinical therapy with anticancer agents.

Topics: Aging; Animals; Antineoplastic Agents; Carbon Radioisotopes; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Female; Lethal Dose 50; Leukemia P388; Leukemia, Experimental; Mice; Mice, Inbred Strains; Mitoguazone; Neoplasm Transplantation; Tissue Distribution

The oxidation of dihydroambazone (1) by oxygen is dependent on the pH-values of the solutions used. This transformation can be inhibited and excluded, respectively, by ascorbic acid using defined concentrations. The oxidation product ambazone (2) was determined spectroscopically at different pH-values. The rate of transformation in serum depends on the temperature and can also be inhibited with ascorbic acid.

Topics: Animals; Ascorbic Acid; Biotransformation; Hydrogen-Ion Concentration; Mitoguazone; Oxidation-Reduction; Rats; Temperature

Dihydroambazone 1, a soluble derivative of ambazone, was tested with an admixture of ascorbic acid (0.1, 0.25, or 0.5% in distilled water) for antineoplastic activity by different routes (i.p., p.o., s.c., i.v.) against leukemia P388, and by s.c. application against Lewis lung carcinoma on B6D2F1-mice. The results were compared with that of ambazone. 1 was as active as ambazone upon the per os d 1-4 schedule only. Ascorbic acid, added for stabilization of 1, had no significant influence on the results. Intravenously given 1 was of low activity. It proved to be toxic at 100 mg/kg body mass. The i.v. toxicity was estimated approximately on B6D2F1-mice (LD50: 150 mg/kg; LD100: 175 mg/kg; maximum tolerated dose (MTD): 100 mg/kg. A comparison between the MTD's of 1 and ambazone in mice and rats (Wistar) showed partly a somewhat better p.o. compatibility of 1. The expectation of a favourable i.v. applicable derivative from the otherwise in water nearly insoluble ambazone could not be realized.

Topics: Animals; Antineoplastic Agents; Lethal Dose 50; Leukemia P388; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Inbred Strains; Mitoguazone; Rats; Rats, Inbred Strains

The influence of 1,4-benzoquinone-guanylhydrazone-thio-semicarbazone (1; ambazone), toluquinone-guanylhydrazone-thiosemicarbazone (2; ambazone 82/80) and p-(thio-semicarbacido)-diaminomethylenehydrazino benzene (3; dihydroambazone) on phytomitogen induced stimulation processes of human lymphocytes was studied. Con A- or PHA-stimulated lymphocytes of healthy probands were treated in vitro with the drugs and the DNA synthesis rate was evaluated by the use of the 3H-labelled thymidine incorporation. A concentration dependent inhibition of the DNA synthesis rate in a comparable quantity for all the tested drugs was found. DNA synthesis was inhibited nearly completely by drug application in a concentration range of 10(-4) mol/l. To check for a possible interference of mitogen stimulation and drug action, 3 was added to the lymphocyte cultures either together with PHA, prior to or after addition of the mitogen. Experiments showed, the sooner the drug acted on the stimulation process, the stronger the DNA synthesis was inhibited.

Topics: Concanavalin A; DNA; Humans; In Vitro Techniques; Lymphocyte Activation; Lymphocytes; Mitoguazone; Phytohemagglutinins; Thymidine

Topics: Animals; Body Weight; Female; Melanoma, Experimental; Mice; Mitoguazone; Organ Size; Tissue Distribution

The antineoplastic activity of 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone (ambazone) against murine leukemia P388 was found to be markedly reduced in 12- and 18-month-old mice as compared to young animals. The immune response against sheep red blood cells (SRBC), a T cell-dependent antigen, was also strongly diminished in tumor-free old mice and was further suppressed after ambazone treatment. Since the antileukemic effect of ambazone disappeared more or less in congenitally athymic nude mice, in neonatally thymectomized or silica-pretreated animals, it has been concluded that the action of the compound seems to be limited to young adult immunocompetent tumor-bearing hosts. Therefore immunosenescence, primarily of T cell functions of old tumor-bearers, may represent a decisive factor influencing the antileukemic, especially curative effect of ambazone in aged animals. A combined treatment with ambazone and immunomodulators (thymalin or a splenopentin derivative) failed to improve the antileukemic effect in young and old leukemia P388-bearing mice.

Topics: Adjuvants, Immunologic; Aging; Animals; Antineoplastic Agents; Female; Immune System; Immunosuppression Therapy; Leukemia P388; Leukemia, Experimental; Mice; Mice, Inbred DBA; Mice, Inbred Strains; Mitoguazone; Peptide Fragments; Thymopoietins; Thymus Hormones; Tissue Extracts

Mice and rats of various ages (3, 10-12, and 18-19 months) were inoculated with the transplantation tumours murine melanoma B16 (B16), mammary adenocarcinoma 755 (Ca-755), leukemia P388 (P388), and rat rhabdomyosarcoma RA-2 (RA-2). Subcutaneous (sc) growth of B16 was not markedly affected by the age of the syngeneic host whereas intravenously (iv) inoculated 12 months old C57BL/6 mice developed more pulmonary metastases than animals 3 months of age. Median survival time (MST) of 18 months old mice bearing Ca-755 was significantly shorter than that of younger individuals. In contrast, old rats that had been injected RA-2 iv survived longer than controls. Survival of DBA/2 mice inoculated intraperitoneally (ip) with P388 cells was not influenced by the age of the host. The antineoplastic activity of ambazone and, to a less extent, of 5-fluorouracil against P388 was drastically lower in 12 months old mice than in 3 months old tumour bearers. Likewise a graduate loss of antineoplastic activity of ambazone against Ca-755 was observed with increasing age of the mice, whereas the effect of ambazone and 5-fluorouracil against RA-2 did not depend on the age of the rats. It is suggested that tumour-host interactions as well as pharmacokinetics of a given drug may underlie age-related changes.

Topics: Adenocarcinoma; Aging; Animals; Antineoplastic Agents; Cell Division; Female; Fluorouracil; Leukemia P388; Leukemia, Experimental; Male; Mammary Neoplasms, Experimental; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Mitoguazone; Neoplasm Metastasis; Rats; Rhabdomyosarcoma

In rats, the pharmacokinetics of 14C-ambazone after i.v. and oral administration was studied. The results demonstrate that the compound is incompletely absorbed from the gastrointestinal tract, penetrates rapidly and to a high degree into various tissues and is preferentially eliminated via the kidneys. After i.v. administration of 50 mg/kg b.m. disposition half-life in whole blood is about 6-7 h. The extent of absorption from the gastrointestinal tract is about 40%.

Topics: Administration, Oral; Animals; Antineoplastic Agents; Bile; Feces; Injections, Intravenous; Male; Mitoguazone; Rats; Rats, Inbred Strains

There is some evidence in the literature that the pharmacokinetics of anticancer agents can be influenced by the presence of a tumor. Therefore several authors recommend pharmacokinetic studies of such drugs to be performed also in tumor-bearing animals (2, 5, 7). The aim of the present study was to evaluate the influence of different stages and routes of inoculation of leukemia P 388 in B6D2F1-hybrid mice on the tissue distribution of ambazone, a new potential antineoplastic drug. It could be emphasized that the drug levels in liver, kidneys and thymus were higher in advanced tumor-bearing than in control animals whereas in the spleen and in whole blood the opposite was true. The differences can be explained partially by changes in the erythrocyte binding of ambazone.

Topics: Animals; Antineoplastic Agents; Carbon Radioisotopes; Female; Kidney; Leukemia P388; Leukemia, Experimental; Liver; Male; Mice; Mitoguazone; Research Design; Spleen; Thymus Gland

Three spontaneous lymphomas of 23- to 24-month-old (AB/Jena X DBA/2 Jena)F1 females were serially transplanted into syngeneic hosts. They were histologically classified as malignant lymphoblastic lymphomas (ABDt2 and ABDt5) and as a malignant lymphoma of histiocytic type (ABDt6). All lymphomas disseminated into the liver, spleen, and pancreas, whereas ABDt2 and ABDt5 additionally infiltrated the bone marrow and leptomeninx. None of the tumors showed a leukemic growth form, but extreme granulocytosis was observed in leukemia P388-bearing mice. Since the lymphomas ABDt2 and ABDt5 expressed T-cell differentiation antigens Ly-1, Ly-2, and Ly-3, they are thought to be of T-cell origin. On the contrary to the lymphocytes of parental mouse strain ABDt2 and ABDt5 cells reacted with anti H-2.23 allosera. All tumors have been found to be sensitive to at least 5/7 clinically used anticancer drugs. But only ABDt2- and P388-bearing mice survived longer than 60 days after treatment with the potent anticancer drug 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone (ambazone). Successful chemotherapy of both tumors was accompanied with resistance of the hosts against the second transplant of the same tumor. Summarizing the characteristics of the newly established transplantation tumors it is concluded that they can be recommended as screening models in the search for new antineoplastic agents.

Topics: Animals; Antineoplastic Agents; Drug Screening Assays, Antitumor; Female; Leukemia P388; Leukemia, Experimental; Lymphoma; Mice; Mitoguazone; Neoplasm Transplantation

Topics: Animals; Antineoplastic Agents; Kinetics; Male; Mice; Mice, Inbred Strains; Mitoguazone

The synthesis of S-substituted derivatives of 1,4-benzoquinone-guanylhydrazone-thiosemicarbazone is described. The obtained 1,4-benzoquinone-guanylhydrazone-S-alkyl (resp. aralkyl)-isothiosemicarbazones, in comparison with the unsubstituted standard compound, showed a significantly decreased biological activity against the murine leukemias L 1210 and P 388 as well as against the growth of several kinds of bacteria. Therefore the S-substitution seems not to be useful for reaching a maximum activity.

Topics: Animals; Anti-Bacterial Agents; Antineoplastic Agents; Bacteria; Leukemia L1210; Leukemia P388; Mice; Microbial Sensitivity Tests; Mitoguazone; Structure-Activity Relationship

Topics: Animals; Cricetinae; Female; Guanidines; Male; Melanoma; Mesocricetus; Mice; Mice, Inbred Strains; Mitoguazone; Neoplasms, Experimental; Skin Neoplasms

By means of four murine models, the authors demonstrated in vivo that 1,4-benzoquinone guanylhydrazone thiosemicarbazone (1), which is known to be antimicrobially active, and its hydrochloride (2) exert an antineoplastic effect. In leukaemia P 388 and leukaemia L 1210 both compounds had a curative action already after four oral administrations. The "cured" animals were resistant or cross-resistant to further transmissions of leukaemia. The resistance was transmissible by splenocytes.

Topics: Animals; Antineoplastic Agents; Carcinoma 256, Walker; Drug Resistance; Guanidines; Kinetics; Leukemia L1210; Leukemia P388; Leukemia, Experimental; Male; Mice; Mice, Inbred Strains; Mitoguazone; Neoplasms, Experimental; Rats

Topics: Animals; Antineoplastic Agents; Guanidines; Mice; Mitoguazone; Neoplasms, Experimental; Rats